This section provides background information related to the present disclosure which is not necessarily prior art.
A method for regulating an exhaust-gas aftertreatment device of the type used with internal combustion engines is known from the publication “Control of a Combined SCR on Filter and Under-Floor SCR System for Low Emission Passenger Cars”, Balland et al, SAE Int. J. Engines, Volume 7, Issue 3. This publication describes regulation of an exhaust-gas aftertreatment device having a first SCR component which is arranged in a vicinity of an engine block, and having a second SCR component which is arranged further away from the engine block. Both SCR components have, in dependence on a quantity of stored ammonia, a corresponding loading state. The first SCR component is regulated by way of a control unit in such a way that the first SCR component has as high a loading of ammonia as possible and thus has a high efficiency for a conversion of nitrogen oxides. A target loading of the first SCR component is determined, in this case, in dependence on a detected loading state of the second SCR component.
The detected loading state of the second SCR component is thus able to limit a value range of the target loading of the first SCR component. Consequently, an efficiency of the first SCR component which is to be achieved and an achievable total efficiency of the exhaust-gas aftertreatment device are limited. Within the framework of future stricter exhaust gas regulations, in particular those concerning emissions of nitrogen oxides, such limitations in the achievable total efficiency may be a disadvantage.